The present invention relates generally to testing of electronic devices. More particularly, the present invention relates to a cellular Radio Frequency (RF) mobile station production/testing and statistical monitoring process.
Prior art production methodology relied on centralized testers doing long arduous test plans and catching process problems long after they occurred. The testers were then considered suspect until proven innocent at which point the actual proximate cause could be investigated and corrected. Often after significant numbers of unsound and unreliable product were built, and subsequently a massive rework effort ensued. This results in wasted product, money, and resources.
Prior art test/production methodology uses an aging, centralized process with very expensive Automated Test Equipment (ATE) and fixture equipment. ATE is a chassis populated with instruments, controlled by a computer, which controls various measurements and tests on a Device Under Test (DUT), and records results fixture equipment. Because the testing is centralized in RF shielded fixtures, (essentially miniature RF chambers), expensive manipulation systems or more expensive and less reliable human operators are required to pick and place DUTs into testers. Valuable time is wasted as the DUT is drawn into the fixture, interfaces are engaged, and power is applied to the DUT. With some electronic devices such as mobile stations, there is a latency or delay between the application of power and when the device is ready or xe2x80x9cawake.xe2x80x9d When the DUT is finally xe2x80x9cawakexe2x80x9d the DUT must be placed in the conditions for the test. Finally, a given ATE instrument may perform an action upon the DUT and then sit idle while all other measurements and actions are performed. Once all actions are complete, the DUT is disengaged, extracted, picked and placed back to the conveyor, and sent to the next stage of production. Actual idle time by the ATE instruments may be around 80%. ATE equipment is expensive with average costs in the six figure range. Therefore, it is desirable to reduce idle time and increase the productivity of any ATE.
Prior art processes require automated testing of displays and user interfaces of the DUT in the tester by key press robots. A key press robot is usually contained inside a final user interface test fixture and is used for mechanically interfacing a device under test. The key press robot is RF shielded and is a xe2x80x9cdrawer-like slide mechanism with a fixture adapter mounted on it. The fixture adapter is specific for the device. The adapter clamps, grabs, or secures the device depending on the type of fixture and the specific attachment surfaces of the device. The adapter also interfaces ear phone jacks, power, etc., and the slide is drawn into the fixture pneumatically.
Once inside the fixture, the device is run through a series of functions and responses are measured to ensure it falls within acceptable limits. In an example of an embodiment of the present invention, a mobile station is the electronic device. A display test is run measured with a sophisticated vision system to ensure all the LEDs, display patterns, keypad backlights etc are functionally sound and reliable. Audio tests measure the speakers and microphones. The phone is brought up into a call and it""s transmitter/receiver tuning and power accuracy is measured. A pneumatic robot finger presses each key and ensures that every one functions, does not jam, and the like. Because it""s pneumatic it""s relatively slow.
The speed of a key press robot becomes the bottleneck. There is a delay caused by power-up of the Device Under Test (DUT) and the pneumatic fingers. Testing at the point of assembly allows better process verification, and places responsibility with the process or vendor quality.
Production and testing systems are monitored by an experienced human. A human supervising the process with undivided attention is still unable to effectively monitor and identify a yield-threatening trend. The intricacy and range of data managed by a single tester in production is currently difficult for less than experienced engineers. The ability for many individuals to further understand and correlate the measurement values and hidden inter-relationships is exponentially complex when stages of 10 testers are aggregated, compounded yet again by correlating inter-relationships between test stages.
In the cellular handset production arena, the current production/test methodology to produce cellular handsets will require a 400% increase in current test equipment, manpower, and floor space.
Earlier production methodology relied on centralized testers doing long arduous test plans, and catching process problems long after they occurred. The testers were then considered suspect until proven innocent at which point the actual proximate cause could be investigated and corrected. Often after significant numbers of unsound and unreliable product was built, and subsequently a massive rework effort ensued. Testers are often relied upon to xe2x80x9ctestxe2x80x9d quality into the system. There is a need to verify processes at the point of operation, and identify problems early.
Prior to the advent of the present invention, monitoring consisted of technicians and supervisors standing in front of a monitor flipping through displays. If experienced, they can identify trends as they became statistically significant. Often that effort is investigative, only drawing attention after the problem becomes significant. Even experienced monitors may have problems monitoring multiple testers with their exponentially increasing complexity as stated above. Other methods for monitoring included exhaustive Statistical Process Control (SPC) tools which required highly trained and competent engineers targeting specific points of data not close to real-time.
It is in light of this background information related to the production and testing of electronic devices that the significant improvement of the present invention has evolved.
Embodiments of the present invention, accordingly, advantageously provide a cellular RF handset production/testing and statistical monitoring process.
Provided is an advanced process for moving a Device under Test (DUT) from surface mount to completion and shipping. The process takes a raw populated Printed Circuit Board (PCB) panel or similar article of manufacture and conducts all possible solder, electrical, boundary scan and flashed self-testing.
Individual panels are routed out of larger panels and placed into basic electronic device chassis on a motorized and power delivering fixture carrying a fixture adapter to interface with the electronic device. Power is provided as soon as is feasible in order to leverage the DUTs ability to facilitate it""s own functional certification. Without power, the xe2x80x9cwake-upxe2x80x9d time for an electronic device may be extensive. For example, the wake-up time for a mobile station is 5 to 15 seconds. Additionally, the addition of power would otherwise have to be done numerous times throughout the process. Conditions for impending measurement can be set up on a powered electronic device so that measurements may be made the moment the testing instrumentation is ready to take measurements.
The DUT is interfaced and carried by a fixture adapter modified to mate the specific model DUT. The fixture adapter is mounted aboard a fixture, which serves as vehicular, power source, and communication suite for the adapter. The individual fixture has an addressable code. This code may be an internet address or the like. The code may also be analogous in form and function to a phone number. Using RF communication, the fixtures report to and are directed by a master control system which tracks progress and measurement results through each stage of assembly.
Various required measurements, tests, and software instructions are conducted wirelessly in a distributed fashion while the DUT advances through the process. Wireless methods, for example, include Radio Frequency Identification (RFID) BLUETOOTH, and cellular RF out of phase with production. Other distributed tests include image capture verification of component placement within tolerance windows, electrical contact presence and alignments, and display activation. Assembly and component verification is tested at or following the point of assembly wherever possible. All occur while the DUT continues to advance. Speed of the DUT may be regulated to allow a test completion or to xe2x80x9ccatch-upxe2x80x9d within the process.
Where actual Baseband, RF, and transmitter power tuning/measuring are required, the DUT enters an RF shielded cell with robotic arms which xe2x80x9cjackxe2x80x9d into moving fixture adapters.
DUT physically moves on its dedicated fixture/fixture adapter during the production process with a goal of never halting until either packed for shipping or out of the process as a failure. Once all standards are met, the DUT is certified. The handset routes to an off-loading, labeling and packaging cell.
Overall measurement results are monitored by an Artificial Intelligence (Al) system in near real-time. Yield and process trend patterns are identified/reacted to according to established rule-sets governing process situations and/or notification of human authorities.
An aspect of an embodiment of the present invention, tests are distributed, actual centralized test time is limited to absolute minimum and all instruments are efficiently utilized. Because the test time and utilization rate is so much higher, fewer ATE are required.
Another object of an embodiment of the invention provides for reduced size ATEs (e.g. from 1.6 meters tall and 800 lbs., to the size of a suitcase and portable).
An further object of an embodiment of the invention provides a quick cycle time in production.
A still further object of an embodiment of the invention is speed. PXI interface is 100 times faster than current General Purpose Interface Bus (GPIB) interface.
Additionally, PXI instruments don""t have to be pulled from production and calibrated yearly, only the communications paths need to be routinely calibrated. Warehouses full of expensive instruments do not have to be stored, transported, integrated into equally expensive racks. Logistics overhead to merely obtain and support the equipment is reduced.
Implementation of an embodiment, or various combinations of embodiments of the present invention facilitates the production and testing of an electronic device. The process also provides for statistical monitoring of the Device Under Test (DUT).
A more complete appreciation of the present invention and the scope thereof can be obtained from the accompanying drawing which are briefly summarized below, the following detailed description of the presently-preferred embodiment of the invention, and the appended claims.